FEASIBILITY OF MEASURING THE EFFECT OF KNEE INJURY PREVENTION TRAINING ON DYNAMIC ACL LENGTH DURING JUMP LANDING

摘要

Anterior cruciate ligament (ACL) injuries are very common, causing pain, loss of function, and medical expense. Women sustain ACL injuries more often than men. Most of these injuries (70%) are non-contact for women [1], occurring during pivoting or sudden deceleration [2]. Training programs have been developed to try to prevent these injuries in women. These programs are designed to improve strength, muscle balance, and knee control. Evaluating the effectiveness of training programs is difficult. To date, these evaluations have only assessed factors such as muscle activation and joint angles that are not directly related to ACL strain and ACL injury risk. Strain levels at ACL failure during slow stretching are in the range of 8 - 12% [3], but failure could occur at lower strain levels if loads were applied more rapidly. For a typical adult, these strain levels suggest ACL failure could occur with an increase in length of approximately 3 mm. Therefore, a measurement system with accuracy substantially lower than 1 mm is necessary in order to study ACL function. The purpose of this pilot study was to test the feasibility of measuring dynamic ACL length in-vivo before and after injury prevention training to assess the effectiveness of the training.